From: Michel Lespinasse <walken@google.com>
Date: Thu, 10 Feb 2011 23:01:33 +0000 (-0800)
Subject: mlock: do not munlock pages in __do_fault()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=419d8c96dbfa558f00e623023917d0a5afc46129;p=linux-beck.git

mlock: do not munlock pages in __do_fault()

If the page is going to be written to, __do_page needs to break COW.

However, the old page (before breaking COW) was never mapped mapped into
the current pte (__do_fault is only called when the pte is not present),
so vmscan can't have marked the old page as PageMlocked due to being
mapped in __do_fault's VMA.  Therefore, __do_fault() does not need to
worry about clearing PageMlocked() on the old page.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/memory.c b/mm/memory.c
index 32df03cf13a5..8e8c18324863 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3051,12 +3051,6 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 				goto out;
 			}
 			charged = 1;
-			/*
-			 * Don't let another task, with possibly unlocked vma,
-			 * keep the mlocked page.
-			 */
-			if (vma->vm_flags & VM_LOCKED)
-				clear_page_mlock(vmf.page);
 			copy_user_highpage(page, vmf.page, address, vma);
 			__SetPageUptodate(page);
 		} else {